1. Field of Inventive Concepts
The inventive concepts disclosed herein generally relate to non-contact position detection and more particularly, but not by way of limitation to optical position detection and analysis of reagent test pads for medical diagnostics via a reagent card alignment system.
2. Brief Description of Related Art
Reagent test strips are widely used in the fields of medicine and clinical chemistry. A test strip usually has one or more test areas, and each test area is capable of undergoing a color change in response to contact with a liquid specimen. The liquid specimen usually contains one or more constituents, substances, or properties of interest. The presence and concentrations of these constituents of interest in the specimen are determinable by an analysis of the color changes undergone by the test strip. Usually, this analysis involves a color comparison between the test area or test pad and a color standard or scale. In this way, reagent test strips assist physicians in diagnosing diseases and other health problems.
To satisfy the needs of the medical profession, as well as other expanding technologies, such as the brewing industry, chemical manufacturing, etc., a myriad of analytical procedures, compositions, and tools have been developed, including the so-called “dip-and-read” type reagent test devices. Regardless of whether dip-and-read test devices are used for the analysis of a biological fluid or tissue, or for the analysis of a commercial or industrial fluid or substance, the general procedure involves a test device coming in contact with the sample or specimen to be tested, and manually or instrumentally analyzing the test device.
Testing tools and methods have been sought in the art for economically and rapidly conducting multiple tests, especially via using automated processing. Automated analyzer systems have an advantage with respect to cost per test, test handling volumes, and/or speed of obtaining test results or other information over manual testing.
A recent development is the introduction of multiple-profile reagent cards and multiple-profile reagent card automated analyzers. Multiple-profile reagent cards are essentially card-shaped test devices which include a substrate and multiple reagent-impregnated pads (or matrices) positioned onto the substrate, for simultaneously or sequentially performing multiple analyses of analytes, such as the one described in U.S. Pat. No. 4,526,753, for example, the entire disclosure of which is hereby expressly incorporated herein by reference.
Multiple-profile reagent cards result in an efficient, economical, rapid, and convenient way of performing automated analyses. Automated analyzers configured to use multiple-profile reagent cards typically take a multiple-profile reagent card, such as from a storage drawer, or a cassette, and advance the multiple-profile reagent card through the analyzer over a travel surface via a card moving mechanism. The card moving mechanism may be a conveyor belt, a ratchet mechanism, a sliding ramp, or a card-gripping or pulling mechanism, for example. As the multiple-profile reagent card is moved or travels along the travel surface, one or more sample dispensers (e.g., manual or automatic pipette or pipette boom) may deposit or dispense one or more samples or reagents onto one or more of the reagent pads. Next, the multiple-profile reagent card may be analyzed (e.g., manually or automatically) to gauge the test result, such as via an optical imaging system, a microscope, or a spectrometer, for example. Finally, the used reagent card is removed from the analyzer, and is discarded or disposed of in an appropriate manner.
During the manufacturing of multiple-profile reagent cards, the reagent pads are generally attached in rows (e.g., to form one or more test strips) onto the substrate of the reagent card. However, typical manufacturing tolerances allow for a possible variance of about 2 mm of the positions of the rows of reagent pads relative to the substrate of the reagent card, with adjacent rows of reagent pads typically being separated by about 5 mm from one another.
Further, as reagent pads are generally rectangular in shape, it is optimal to deposit the sample substantially at the center of a reagent pad or at a central region of the reagent pad to help ensure thorough saturation of the reagent pad with sample, and to substantially prevent the sample from leaking out of the reagent pad and onto the substrate of the reagent card or into adjacent reagent pads.
Due to the need to precisely dispense the sample onto the reagent pad and the fact that reagent pad positions on the reagent card have relatively large manufacturing tolerances, it is important for automated analyzers to precisely locate the reagent pad on the multiple-profile reagent card prior to depositing the sample thereon.
Multiple prior art systems have attempted to resolve this problem without success. Several such systems are contact systems, which are complicated and inaccurate, and may cause misfeeding of reagent cards or damage to the reagent cards or reagent pads by contacting them.
To that end, a need exists in the prior art for a non-contact optical method and alignment system for precisely determining the positions of reagent cards and of one or more reagent pads on the reagent cards. It is to such optical card alignment systems and methods that the inventive concepts disclosed herein are directed.